Method for qualitative and quantitative multiplexing of drug analytes from biological samples

ABSTRACT

A method for qualitative and quantitative multiplexing of drug analytes from dried blood samples includes the steps of mixing an Internal Standard solution with a first diluent in a vessel, adding the dried blood sample to the vessel, sonicating the vessel containing the Internal Standard solution, the first diluent and the dried blood sample, removing the dried blood sample from the vessel so that a final sample can be attained, and analyzing at least a portion of the final sample using one of LC-MS and LC-MS/MS to simultaneously determine the presence or absence of a plurality of different analytes in the dried blood sample. The Internal Standard solution can include at least 8, 15, 25 or 50 Internal Standards. The dried blood sample is generated using less than 50 μL, 20 μL or 10 μL of blood. The step of analyzing includes simultaneously determining the presence or absence of at least 15, 60, 90 or 130 different analytes. A ratio of the number of analytes for which the presence or absence is being determined to the number of Internal Standards in the Internal Standard solution is at least approximately 2:1. A ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of the final sample being analyzed is at least approximately 2:1. A ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of blood from which the dried blood sample was obtained is at least approximately 4:5.

RELATED APPLICATION

This application claims priority on U.S. Provisional Application Ser. No. 62/639,713, filed on Mar. 7, 2018, and entitled “MULTIPLEXING METHOD FOR DRIED BLOOD ANALYSIS USING A NON-CARD MICRO SAMPLING DEVICE TO PERFORM QUANTITATIVE/QUALITATIVE DRUG ANALYSIS, GENETIC ANALYSIS, AND IMMUNOASSAY ANALYSIS”. To the extent permitted, the contents of U.S. Provisional Application Ser. No. 62/459,996 are incorporated in their entirety herein by reference.

BACKGROUND

Liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS) are analytical chemistry techniques that combine the physical separation capabilities of high performance liquid chromatography (or HPLC) with the mass analysis capabilities of mass spectrometry (MS). These systems are popular in chemical analysis because the individual capabilities of each technique are enhanced synergistically. While liquid chromatography separates mixtures with multiple components, mass spectrometry provides structural identity of the individual components with high molecular specificity and detection sensitivity.

In recent years, liquid chromatography tandem mass spectrometry (LC-MS/MS) has emerged as an innovative analytical technology applicable to some analyses in the endocrinology laboratory. In tandem MS (MS/MS) two quadrupole mass filters are combined and target analyte molecules from the first quadrupole are submitted to a controlled fragmentation in a collision cell. The entirety of ions is transferred into the first quadrupole mass filter. Here, the mass-to-charge ratio (m/z) of the intact ionized target analyte is selected, and all other ion species are filtered out. The selected ions sharing identical m/z are continuously transferred into the collision cell. Ions selected by the first quadrupole fragment into characteristic product ions. For various analytes, several characteristic, thermodynamically favored product ions are generated. These fragment ions are guided to the second quadrupole. The radiofrequency settings of the second analytical quadrupole are adjusted in a way that only one selected fragment ion will pass, while all other fragment ion species are filtered out. Thus, one defined “daughter ion” from one defined “parent ion” finally reaches an ion detector, and can then be identified and/or quantified.

Many medical procedures require tests to be performed with a sample of a patient's fluid. The ability to rapidly and accurately detect a wide range of analytes present in a bodily fluid is often critical for diagnosis, prognosis, and treatment of diseases, or for determining specific drugs that may be present in a patient's system.

Traditionally, detecting a range of analytes present in a bodily fluid such as blood has been performed in laboratories by trained technicians who take blood via venipuncture or using smaller blood samples such as by a finger stick. Performing such assays using LC-MS or LC-MS/MS can be time-consuming and costly. Running dozens or even hundreds of such tests to determine the presence (or absence) and/or quantity of various analytes characteristically requires a relatively large volume of blood. With conventional techniques, it is difficult to simultaneously test for a relatively large number of analytes. Consequently, each test requires a certain quantity of blood. The greater number of tests that are required, the greater the volume of blood that is needed from the patient.

Although several point of care testing devices are available, the majority of are adapted to detect a single analyte, or one type of analytes for a single indication, Examples of such point of care devices are tests for glucose, serum cholesterol, pregnancy, ovulation, etc.

Thus, there remains a need for alternative testing methods that are capable of detecting a wider range and/or greater number of analytes from biological samples such as dried blood, urine and/or other biological samples. A desirable system would allow quantitative and qualitative measurements of analytes in a more cost effective and timely manner.

SUMMARY

The present invention is directed toward a method for qualitative and quantitative multiplexing of drug analytes from a dried blood sample. In one embodiment, the method includes the steps of mixing an Internal Standard solution with a first diluent in a vessel, the Internal Standard solution including a plurality of different Internal Standards, adding the dried blood sample to the vessel, sonicating the vessel containing the Internal Standard solution, the first diluent and the dried blood sample, removing the dried blood sample from the vessel so that a final sample can be attained, and analyzing at least a portion of the final sample using one of LC-MS and LC-MS/MS to simultaneously determine the presence or absence of a plurality of different analytes in the dried blood sample.

In certain embodiments, the Internal Standard solution includes at least 8, 15, 25 or 50 Internal Standards.

In various embodiments, the dried blood sample is generated using less than 50 μL, 20 μL or 10 μL of blood.

In some embodiments, the first diluent can be methanol. Alternatively, wherein the first diluent can include water and methanol.

wherein a ratio of the volume of the water to the volume of the methanol is less than 1:1. Alternatively, the ratio of the volume of the water to the volume of the methanol is approximately 1:4.

In certain embodiments, the method further includes the step of adding a second diluent after the step of removing the dried blood sample from the vessel. In some embodiments, the second diluent can be water.

In various embodiments, the volume of the second diluent can be substantially similar to the volume of the first diluent.

In some embodiments, the step of analyzing includes simultaneously determining the presence or absence of at least 15, 60, 90 or 130 different analytes.

In certain embodiments, the step of analyzing includes using one of LC-MS and LC-MS/MS in a positive ionization mode. Alternatively, the step of analyzing can include using one of LC-MS and LC-MS/MS in a negative ionization mode.

In various embodiments, a ratio of the number of analytes for which the presence or absence is being determined to the number of Internal Standards in the Internal Standard solution is at least approximately 2:1 or at least approximately 5:1.

In some embodiments, a ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of the final sample being analyzed is at least approximately 2:1 or at least approximately 5:1.

In certain embodiments, a ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of blood from which the dried blood sample was obtained is at least approximately 4:5, 3:1, 9:2 or 6:1.

In another embodiment, the present invention is directed toward a method for qualitative and quantitative multiplexing of drug analytes from a dried blood sample that has been obtained from not greater than 20 μL of blood. In one embodiment, the method includes the steps of mixing an Internal Standard solution with a first diluent in a vessel, the Internal Standard solution including at least two Internal Standards, adding the dried blood sample to the vessel, sonicating the vessel containing the Internal Standard solution, the first diluent and the dried blood sample, removing the dried blood sample from the vessel so that a final sample can be attained, and analyzing at least a portion of the final sample using one of LC-MS and LC-MS/MS to simultaneously determine the presence or absence of a plurality of different analytes in the dried blood sample; wherein a ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of blood from which the dried blood sample was obtained is greater than approximately 3:1.

In yet another embodiment, the present invention is directed toward a method for qualitative and quantitative multiplexing of drug analytes from a dried blood sample, the dried blood sample that has been obtained from less than 20 μL of blood. In this embodiment, the method includes the steps of mixing an Internal Standard solution with a first diluent in a vessel, the Internal Standard solution including a plurality of Internal Standards, adding the dried blood sample to the vessel, sonicating the vessel containing the Internal Standard solution, the first diluent and the dried blood sample, removing the dried blood sample from the vessel so that a final sample can be attained; and analyzing at least a portion of the final sample using one of LC-MS and LC-MS/MS to simultaneously determine the presence or absence of at least 16 different analytes in the dried blood sample; wherein a ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of blood from which the dried blood sample was obtained is greater than approximately 3:1.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying figures, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:

FIG. 1 is a flow chart showing one embodiment of a method for qualitative and quantitative multiplexing of drug analytes from a dried blood sample using a positive ionization mode during mass spectrometry;

FIG. 2 is a flow chart showing one embodiment of a method for qualitative and quantitative multiplexing of drug analytes from a urine sample using a positive ionization mode during mass spectrometry;

FIG. 3 is a flow chart showing another embodiment of a method for qualitative and quantitative multiplexing of drug analytes from a dried blood sample using a negative ionization mode during mass spectrometry; and

FIG. 4 is a flow chart showing another embodiment of a method for qualitative and quantitative multiplexing of drug analytes from a urine sample using a negative ionization mode during mass spectrometry.

DESCRIPTION

Embodiments of the present invention are described herein in the context of a method for qualitative and quantitative multiplexing of drug analytes from biological samples such as dried blood, urine and/or other suitable biological samples. Those of ordinary skill in the art will realize that the following detailed description of the present invention is illustrative only and is not intended to be in any way limiting. Other embodiments of the present invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. Reference will now be made in detail to implementations of the present invention as illustrated in the accompanying drawings.

In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It will, of course, be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made in order to achieve the developer's specific goals, such as compliance with application-related and business-related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure.

Further, it is understood that although the description herein regarding biological samples is somewhat directed toward analysis of dried blood samples and urine samples, such is provided for the sake of clarity and simplicity. It is recognized that other suitable biological samples can equally and effectively be analyzed utilizing one or more of the methods disclosed herein. The types of dried blood samples can vary, and can include, without limitation, samples obtained via Neoteryx® blood collection devices, as one non-exclusive example. As used herein, the dried blood samples are generated from relatively small volumes of blood. For example, in one embodiment, the dried blood sample is contemplated to be obtained from less than approximately 50 μL of blood from a patient. In certain non-exclusive, alternative embodiments, the dried blood sample can be obtained from less than approximately 30 μL, 20 μL or 10 μL of blood from the patient.

For at least some of the embodiments shown and described herein, the specific drug analytes can include one or more of the following 303 analytes: 10, 11-Dihydro-10-OH-Carbamazepine, 11-nor-9-carboxy-delta9-THC, 5-Fluoro NPB-22, 5-MeO-DMT, 6-Hydroxy Buspirone, 6-monoacetylmorphine, 7-Aminoclonazepam, 7-HydroxyMitragynine, 9-Hydroxyrisperidone, AB-FUBINACA, Acebutolol, Acetaminophen, Acetazolamide, Acetyl-Fentanyl, Alfuzosin, Alpha-hydroxyalprazolam, Alpha-hydroxymidazolam, Alpha-hydroxytriazolam, Alpha-hydroxy-Metoprolol, Alpha-PVP, Alprazolam, AM2201, Amiodarone, Amitriptyline, Amlodipine, Amobarbital, Amoxapine, Amphetamine, Apixaban, Aripiprazole (Abilify), Asenapine, Atenolol, Atomoxetine, Atorvastatin, Atorvastatin Lactone, Baclofen, Benazeprilat, Benzolyecognine, Biotin, Bisoprolol, Brexpiprazole, Budesonide, Buprenorphine, Bupropion (Wellbutrin), Buspirone, Butabarbital, Butalbital, Butorphanol, Caffeine, Candesartan, Candesartan Cilexetil, Canrenone, Carbamazepine, Carfentanil, Carisoprodol, Carvedilol, Celecoxib, Cetirizine, Chlordiazepoxide, Chlorothiazide, Chlorpheniramine, Chlorpromazine, Cilostazol, Citalopram, Clobazam, Clomipramine, Clonazepam, Clopidogrel, Clozapine, Clozapine N-oxide, Cocaine, Codeine, Colchicine, Cotinine, Cyclobenzaprine, Dabigatran, Darifenacin, Dehydro Aripiprazole, Desalkylflurazepam, Desipramine, Desloratadine, Desmethoxyangonin, Dexamethasone, Dextromethorphan, Diazepam, Diclofenac, Dihydrocodeine, Dihydrokavain, Dihydromethysticin, Diltiazem, Diphenhydramine, Dipyridamole, DMT, Donepezil, Doxazosin, Doxepin, Dronedarone, Duloxetine, EDDP, Eletriptan, Enalaprilat, Ephedrine, Estazolam, Eszopiclone, Ethyl Sulfate (EtS), Ethyl-beta-D-glucuronide (EtG), Etodolac, Ezetimibe, Famotidine, FDU-PB-22, Febuxostat, Fenofibric Acid, Fentanyl, Fexofenadine, Finasteride, Flecainid, Flunitrazepam, Fluoxetine, Fluphenazine, Flurazepam, Fluvoxamine, Furosemide, Gabapentin, Gemfibrozil, Glimepiride, Glipizide, Glyburide, Guanfacine, Haloperidol, HU-210, Hydrochlorothiazide, Hydrocodone, Hydromorphone, Hydroxybupropion, Hydroxychloroquine, Hydroxyzine, Hyoscyamine, Ibuprofen, Iloperidone, Imipramine, Indapamide, Indomethacin, Irbesartan, Itraconazole, JWH-018-5OH-Pentyl Metabolite, JWH-018-5-Pentanoic Acid Metabolite, JWH-019, JWH-073-4OH-butyl-Metabolite, JWH-081, JWH-122, JWH-250-5OH-Pentyl Metabolite, Kavain, Ketamine, Labetalol, Lamotrigine, Lansoprazole, Levetiracetam, Levorphanol, Levothryoxine, Licarbazepine, Linagliptin, Lisdexamfetamine, Lisinopril, Loratadine, Lorazepam, Losartan, Lurasidone, Marinol, MDA, MDEA, MDMA, MDPV, Meloxicam, Meperidine, Mephedrone, Meprobamate, Metaxalone, Metformin, Methadone, Methamphetamine, Methocarbamol, Methotrexate, Methylone, Methylphenidate, Methysticin, Metoclopramide, Metoprolol, Midazolam, Milnacipran, Mirtazapine, Mitragynine, MMB-CHMICA, Montelukast, Morphine, Nadolol, Naloxone, Naltrexone, Naproxen, Nateglinide, N-Desethylamiodarone, N-Desmethylclomipramine, N-Desmethylflunitrazepam, N-DesmethylTramadol, N-Desmethyl-U-47700, Nifedipine, Nitrofurantoin, Norbuprenorphine, Norchlordiazepoxide, Nordiazepam, Norcodeine, Nordoxepin, Norfentanyl, Norfluoxetine, Norhydrocodone, Norketamine, Normephedrone, Normirtazapine, Noroxycodone, Norpropoxyphene, Norquetiapine, Nortriptyline, Nor-U-47700 (Didesmethyl-U-47700), O-DesmethylTramadol, O-DesmethylVenlafaxine, Olanzapine, Olmesartan Acid, Olopatadine, Omeprazole, Omeprazole (Carboxylic Acid Metabolite), Ondansetron, Oxazepam, Oxcarbazepine, Oxipurinol, Oxycodone, Oxymorphone, Pantoprazole, Paroxetine, PCP, Pentobarbital, Pentoxifylline, Perphenazine, Phenobarbital, Phentermine, Phenytoin, Pioglitazone, Piroxicam, Prazepam, Prednisolone, Pregabalin, Primidone, Promethazine, Propoxyphene, Propranolol, Pseudoephedrine, Quetiapine (Seroquel), Raloxifene, Ranitidine, Ranolazine, Repaglinide, Risperidone, Ritalinic Acid, Rivaroxaban, Rivastigmine, Ropinirole, Rosiglitazone, Saxagliptin, Secobarbital, Sertraline (Zoloft), Sildenafil, Simvastatin, Sitagliptin, Solifenacin, Sumatriptan, Tadalafil, Tapentadol, Telmisartan, Temazepam, Terazosin, Thioridazine, Thiothixene, Tiagabine, Ticagrelor, Tofacitinib, Topiramate, Torsemide, Tramadol, Trazodone, Triamterene, Triazolam, Valproic Acid, Valsartan, Vardenafil, Venlafaxine, Verapamil, Vilazodone, Vortioxetine, Warfarin, Yangonin, Zaleplon, Ziprasidone, Zolpidem, Zonisamide and Zopiclone N-Oxide.

FIG. 1 is a flow chart showing one embodiment of a method for qualitative and quantitative multiplexing of drug analytes from biological samples. More specifically, FIG. 1 shows one embodiment of a method for qualitative and quantitative multiplexing of drug analytes from a dried blood sample.

The dried blood sample (or other biological samples) can come from patients under the care of a treating physician from clinics and clinical institutions or from private parties. The methods described herein include novel robust, highly specific and reliable, e.g. free of interference, chromatographic separation methods. It is recognized that in certain embodiments, various steps illustrated and described with respect to FIG. 1 can be omitted without deviating from the scope of the disclosure herein. It is further recognized that in some embodiments, additional steps can be included in the method shown in FIG. 1 that are not illustrated and described. Additionally, it is understood that although dried blood is the biological sample that is specifically described relative to the description of FIG. 1, any other suitable biological sample could equally be utilized. Thus, as used herein, “dried blood sample” is but one example of the “biological sample”. In certain non-exclusive embodiments, the method for qualitative and quantitative multiplexing of drug analytes from a dried blood sample can include one or more of the following steps.

In the embodiment illustrated in FIG. 1, at step 100, an Internal Standard solution and a diluent (also sometimes referred to herein as the “first diluent”) are added to one another in a vessel, such as a 1.2 mL test tube as one representative, non-exclusive example. In one embodiment, a plurality of vessels, i.e. test tubes, can be positioned into a multi-well plate, such as a 96-well plate that can receive 96 test tubes, in one representative example. In this embodiment, the first diluent can be methanol. In non-exclusive alternative embodiments, the first diluent can be acetonitrile, ethanol, acetate, formic acid, or any other suitable diluent that at least partially promotes protein precipitation.

The concentration of the Internal Standard solution can be varied. In various embodiments, the Internal Standard solution can include a plurality of Internal Standards mixed together with a solution that includes methanol and water. In various embodiments, the Internal Standards that are included in the Internal Standard solution can include one or more that are selected from the group consisting of the following 98 Internal Standards: 6-Acetyl-morphine-d6, Acetaminophen-d4, Alprazolam-d5, Amphetamine-d11, Benzoylecgonine-d3, Buprenorphine-d4, Carisoprodol-d7, Cocaine-d3, Codeine-d3, Duloxetine-d3, Diazepam-d5, EDDP-d3, Hydrocodone-d3, Hydromorphone-d3, Imipramine-d3, Levorphanol-d3, Lorazepam-d4, MDA-d5, MDEA-d5, MDMA-d5, Meperidine-d4, Methadone-d3, Methamphetamine-d5, Morphine-d6, Norbuprenorphine-d3, Nordiazepam-d5, Norfentanyl-d5, Noroxycodone-d3, Norpropoxyphene-d5, Oxazepam-d5, Oxycodone d3 (O-methyl-d3), Oxymorphone-d3, PCP-d5, Propoxyphene-D11, Trazadone-d6, Temazepam-d5, Zolpidem-d7, 11-nor-9 carboxy Delta 9-THC-d3, JWH-018 4-Hydroxypentyl-d5, Naloxone-d5, Caffeine-13C3, Lamotrigine-13C, 15N4, Levetiracetam-d6, Zonisamide-13C6, Clozapine-d4, Tiagabine-d6, Oxcarbazepine-13C6, Mephedrone-d3, Methylphenidate-d9, Tramadol-13C-d3, Venlafaxine-d6, Ritalinic Acid-d10, O-Desmethylvenlafaxine-d6, Cotinine-d3, 7-HydroxyMitragynine-d3, Alpha-PVP-d8, Chlordiazepoxide-d5, Clobazam-13C6, Clomipramine-d3, Desalkylflurazepam-d4, Dextromethorphan-d3, Ephedrine-d3, Estazolam-d5, Flunitrazepam-d7, Haloperidol-d4, Ketamine-d4, Lisdexamphetamine-d4, Delta9-THC-d3 (Marinol), MDPV-d8, Methylone-d3, Midazolam-d4, Mitragynine-d3, Naltrexone-d3, Nortriptyline-d3, Phentermine-d5, Prazepam-d5, Risperidone-d4, Triazolam-d4, Zaleplon-d4, Amobarbital-D5, Phenobarbital-D5, Pentobarbital-D5, Butalbital-D5, Butabarbital-D5, Secobarbital-D5, Ethyl-D5 Sulfate, Ethyl Beta D-Glucuronide-D5, (−)-Cotinine-D3, Candesartan-D5, Dexamethasone-D4, JWH-018-N(40H-Pentyl) D5, Lisdexamfetamine-D4, Naltrexone-D3, Norcodeine-D3, Rivaroxaban-D4, Rosiglitazone-D3, Sildenafil-D3 and Telmisartan-D3. It is understood that the foregoing Internal Standards are not intended to be an all-inclusive listing of all possible Internal Standards that can be used with the methods provided herein. Rather, the foregoing Internal Standards are merely a representative listing of various Internal Standards that can be used.

In one embodiment, the Internal Standard solution can have an Internal Standard concentration of approximately 1000 ng/mL. Alternatively, the final product of the Internal Standard solution can have an Internal Standard concentration that is greater or less than 1000 ng/mL. For example, in non-exclusive alternative embodiments, the final product of the Internal Standard solution can have an Internal Standard concentration that is between 100 ng/mL and 10,000 ng/mL. In one embodiment, the water that is used can be HPLC-grade water. Additionally, or in the alternative, the methanol that is used can be HPLC-grade methanol. The ratio of the volume of water to the volume of methanol in the Internal Standard solution can vary. In one embodiment, the ratio of the volume of water to the volume of methanol in the Internal Standard solution can be approximately 1:1. However, in alternative embodiments, the ratio of the volume of water to the volume of methanol in the Internal Standard solution can be greater than approximately 5:1, 4:1, 3:1, 2:1 or 1:1. In other alternative embodiments, the ratio of the volume of water to the volume of methanol in the Internal Standard solution can be less than approximately 1:5, 1:4, 1:3, 1:2 or 1:1. Still alternatively, the plurality of Internal Standards can be mixed with a solution or a compound other than a mixture of water and methanol.

The number of Internal Standards included in the Internal Standard solution can vary depending upon the number and type of analytes being tested in the dried blood sample. For example, in certain tests that include at least 50 analytes being tested simultaneously, a ratio of the number of analytes being tested to the number of Internal Standards in the Internal Standard solution can be less than 2:1. In non-exclusive alternative embodiments, the ratio of the number of analytes being tested to the number of Internal Standards in the Internal Standard solution can be approximately 2:1, or the ratio can be greater than 2:1, greater than 3:1, greater than 5:1, greater than 8:1 or greater than 10:1. In still other embodiments, the ratio of the number of analytes being tested to the number of Internal Standards in the Internal Standard solution can be approximately 90:53, 20:9, 137:16, or any other suitable ratio. In yet other embodiments that include fewer than 50 analytes being tested simultaneously, the ratio of the number of analytes being tested to the number of Internal Standards in the Internal Standard solution can similar to the aforementioned ratios. Still alternatively, the number of Internal Standards that are used in the Internal Standard solution can range from 1-98. In an alternative embodiment, greater than 98 Internal Standards can be used.

Further, the relative volumes of the Internal Standard solution and the diluent can be varied. In one embodiment, the volume of the Internal Standard solution can be approximately 10% of the volume of diluent that is used. For example, in one non-exclusive embodiment, 20 μL of the Internal Standard solution can be added together with 200 μL of the diluent to make a total of 220 μL in the vessel. However, it is recognized that the total volume can be varied as necessary, provided the ratio of the volume of the Internal Standard solution to the volume of diluent is the same. However, in alternative embodiments, the volume of the Internal Standard solution can be greater or less than 10% of the volume of diluent that is used. In certain embodiments, the diluent can be HPLC-grade methanol.

At step 102, the dried blood sample is added to the combination of the Internal Standard solution and the diluent. The form of the dried blood sample can vary. In one non-exclusive embodiment, the dried blood sample can include a Mitra® clamshell blood-absorbing tip manufactured by Neoteryx® that has absorbed a relatively small volume of blood from a patient. For instance, in certain embodiments, the blood-absorbing tip can hold approximately 10-50 μL of blood. It is recognized, however, that any suitable means of obtaining and/or storing a blood sample from a patient can be used. In the embodiment that utilizes a Mitra® clamshell blood-absorbing tip, the blood-infused tip is immersed in the vessel with the combination of the Internal Standard solution and the diluent. The amount of blood that is used to generate the dried blood sample can vary. In one embodiment, the dried blood sample can be generated from an initial amount of blood that is approximately 20 μL. Alternatively, the dried blood sample can be generated from an initial amount of blood that is approximately 10 μL, 30 μL or 50 μL. Still alternatively, the dried blood sample can be generated from an initial amount of blood that is less than 10 μL or greater than 50 μL.

At step 104, the vessel that contains the dried blood sample and the combination of the Internal Standard solution and the diluent is sonicated. One or more vessels (such as a plurality of vessels positioned in a multi-well plate, in one embodiment) each containing a dried blood sample and a combination of the Internal Standard solution and the diluent, can be sonicated simultaneously. Deionized water can be set to approximately 4 degrees Celsius (or higher or lower, as needed), and would be at a sufficient level so that the deionized water is higher than the tip containing the dried blood sample. In one embodiment, sonication can proceed for a total of 2-5 minutes, and can cycle on for 20 seconds and off for 10 seconds. Alternatively, the sonication process can have a duration of less than 2 minutes or greater than 5 minutes. Still alternatively, the on cycle can have a duration of greater or less than 20 seconds, and/or the off cycle can have a duration of greater or less than 10 seconds. During the sonication process, the amplitude setting can be between 70-100%. In one embodiment, the amplitude setting can be approximately 75%.

At step 106, the dried blood tips (or other blood-absorbing material) is removed from the vessel and can be discarded.

At step 108, an additional diluent (also sometimes referred to herein as the “second diluent”) is added to each of the vessels that were sonicated at step 104 to yield a final sample. In one embodiment, the second diluent can be HPLC-grade water. Alternatively, the second diluent can include other compounds or solutions. Further, the second diluent for each vessel can have a volume that is substantially similar or identical to the volume of the first diluent added to each vessel and combined with the Internal Standard solution at step 100. For example, if 200 μL of the first diluent was added to the Internal Standard solution at step 100, an additional 200 μL of the second diluent can be added to the vessel at step 108. Alternatively, a volume of the second diluent that is greater or less than 200 μL can be added during step 108. In this representative example, a total of approximately 420 μL of the final sample would be present in each vessel. It is understood that these amounts are provided herein as one representative example, and are not intended to be limiting in any manner.

At step 110, a portion or all of the final sample in step 108 from a particular vessel can then be analyzed by LC-MS and/or LC-MS/MS to simultaneously determining the presence or absence and quantity of a plurality of analytes in the dried blood sample. It is understood that during a single LC-MS and/or LC-MS/MS analysis, various analytes can be detected at slightly different times. However, as used herein, the term “simultaneously” is intended to mean during a single LC-MS and/or LC-MS/MS analysis. In various embodiments, the positive ionization mode of the LC-MS and/or LC-MS/MS process can simultaneously determine the presence or absence of at least 30 analytes in the dried blood sample. In various non-exclusive alternative embodiments, utilizing the method(s) outlined herein, the positive ionization mode of the LC-MS and/or LC-MS/MS process can simultaneously determine the presence or absence of at least 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 200, 250 or 300 analytes in the dried blood sample. Using the methodology provided herein, a ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of blood from which the dried blood sample was obtained can be at least approximately 1:1. In non-exclusive alternative embodiments, the ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of blood from which the dried blood sample was obtained can be at least approximately 2:1, 3:1, 9:2, 5:1, 6:1, 8:1 or 10:1.

In certain embodiments, the LC-MS and/or LC-MS/MS process can yield evidence of the presence or absence of any single analyte, any combination of analytes, or all of the analytes listed and/or described herein during a single LC-MS and/or LC-MS/MS analysis. The analytes present in the final sample can be determined by any suitable method, including, but not limited to, consulting a lookup table, printouts from the LC-MS and/or LC-MS/MS process, appropriate software, etc.

The volume of the final sample that is needed for LC-MS and/or LC-MS/MS can vary. In various embodiments, the volume of the final sample that is needed is dependent upon the number of analytes being detected and/or analyzed during the LC-MS and/or LC-MS/MS process. For example, in one embodiment, a ratio of the number of analytes to the volume of a portion of the final sample (in μL) that is used during a single LC-MS and/or LC-MS/MS analysis is at least approximately 3:2. In non-exclusive, alternative embodiments, the ratio of the number of analytes to the volume of the portion of the final sample (in μL) that is used during a single LC-MS and/or LC-MS/MS analysis can be at least approximately 2:1, 5:1, 10:1, 15:1 or 20:1. Thus, a relatively large number of analytes can be analyzed during the LC-MS and/or LC-MS/MS process using a relatively small volume of the final sample from step 108. In this manner, numerous retests or reruns of step 110 can occur, if necessary.

FIG. 2 is a flow chart showing one embodiment of a method for qualitative and quantitative multiplexing of drug analytes from a urine sample. It is recognized that in certain embodiments, various steps illustrated and described with respect to FIG. 2 can be omitted without deviating from the scope of the disclosure herein. It is further recognized that in some embodiments, additional steps can be included in the method shown in FIG. 2 that are not illustrated and described. In certain non-exclusive embodiments, the method for qualitative and quantitative multiplexing of drug analytes from a urine sample can include one or more of the following steps.

At step 220, an Internal Standard solution and a urine sample are added to one another in a vessel, such as a 1.2 mL test tube as one representative, non-exclusive example. The preparation of the Internal Standard solution can be substantially similar or identical to preparation of the Internal Standard solution previously described relative to step 100 in FIG. 1.

The number of Internal Standards included in the Internal Standard solution can vary depending upon the number and type of analytes being tested in the urine sample. For example, in certain tests that include at least 50 analytes being tested simultaneously, a ratio of the number of analytes being tested to the number of Internal Standards in the Internal Standard solution can be less than 2:1. In non-exclusive alternative embodiments, the ratio of the number of analytes being tested to the number of Internal Standards in the Internal Standard solution can be approximately 2:1, or the ratio can be greater than 2:1, greater than 3:1, greater than 5:1, greater than 8:1 or greater than 10:1. In still other embodiments, the ratio of the number of analytes being tested to the number of Internal Standards in the Internal Standard solution can be approximately 90:53, 20:9, 137:16, or any other suitable ratio. In yet other embodiments, that include fewer than 50 analytes being tested simultaneously, the ratio of the number of analytes being tested to the number of Internal Standards in the Internal Standard solution can similar to the aforementioned ratios.

The ratio of the volume of the Internal Standard solution and the urine sample can vary. In one embodiment, the ratio of the volume of the Internal Standard solution and the urine sample can be approximately 1:1. However, in non-exclusive alternative embodiments, the ratio of the volume of the Internal Standard solution and the urine sample can be greater than approximately 1:1, 2:1, 3:1, 4:1 or 5:1. Still alternatively, the ratio of the volume of the Internal Standard solution and the urine sample can be less than approximately 1:1, 1:2, 1:3, 1:4 or 1:5.

At step 222, a diluent is added to the mixture of the Internal Standard solution and the urine sample from step 220 to form a final sample. In various embodiments, the diluent can be a solution that includes water and methanol. In one embodiment, the water that is used can be HPLC-grade water. Additionally, or in the alternative, the methanol that is used can be HPLC-grade methanol. The ratio of the volume of water to the volume of methanol in the diluent can vary. In one embodiment, the ratio of the volume of water to the volume of methanol in the diluent can be approximately 1:1. However, in alternative embodiments, the ratio of the volume of water to the volume of methanol in the diluent can be greater than approximately 5:1, 4:1, 3:1, 2:1 or 1:1. In other alternative embodiments, the ratio of the volume of water to the volume of methanol in the diluent can be less than approximately 1:5, 1:4, 1:3, 1:2 or 1:1. Still alternatively, the diluent can comprise compounds other than a mixture of water and methanol.

Further, the relative volumes of the mixture of the Internal Standard solution and the urine sample on the one hand, and the diluent on the other hand, can be varied. In one embodiment, the volume of the mixture of the Internal Standard solution and the urine sample can be approximately 25% of the volume of diluent that is added. For example, in one non-exclusive embodiment, 20 μL of the Internal Standard solution can be added together with 20 μL of the urine sample and 160 μL of the diluent to make a total of 200 μL in each vessel. However, it is recognized that the total volume can be varied as necessary. However, in alternative embodiments, the volume of the mixture of the Internal Standard solution and the urine sample can be greater or less than approximately 25% of the volume of diluent that is added.

At step 224, a portion or all of the final sample from step 222 from a particular vessel can then be analyzed by LC-MS and/or LC-MS/MS to determine the presence, absence and/or quantity of a plurality of analytes in the urine sample. In various embodiments, the positive ionization mode of the LC-MS and/or LC-MS/MS process can simultaneously determine the presence or absence of at least 30 analytes in the urine sample. In various non-exclusive alternative embodiments, utilizing the method(s) outlined herein, the positive ionization mode of the LC-MS and/or LC-MS/MS process can simultaneously determine the presence or absence of at least 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 200, 250 or 300 analytes in the urine sample. In certain embodiments, the LC-MS and/or LC-MS/MS process can yield evidence of the presence or absence of any single analyte, any combination of analytes, or all of the analytes listed and/or described herein during a single LC-MS and/or LC-MS/MS analysis. The analytes present in the final sample can be determined by any suitable method, including, but not limited to, consulting a lookup table, printouts from the LC-MS and/or LC-MS/MS process, appropriate software, etc.

The volume of the final sample that is needed for LC-MS and/or LC-MS/MS can vary. In various embodiments, the volume of the final sample that is needed is dependent upon the number of analytes being detected and/or analyzed during the LC-MS and/or LC-MS/MS process. For example, in one embodiment, a ratio of the number of analytes to the volume of a portion of the final sample (in μL) that is used during a single LC-MS and/or LC-MS/MS analysis is at least approximately 2:1. In non-exclusive, alternative embodiments, the ratio of the number of analytes to the volume of the portion of the final sample (in μL) that is used during a single LC-MS and/or LC-MS/MS analysis can be at least approximately 5:1, 10:1, 15:1, 20:1, 25:1 or 30:1. Thus, a relatively large number of analytes can be analyzed during the LC-MS and/or LC-MS/MS process using a relatively small volume of the final sample from step 222. In this manner, numerous retests or reruns of step 224 can occur, if necessary.

FIG. 3 is a flow chart showing another embodiment of a method for qualitative and quantitative multiplexing of drug analytes from a dried blood sample using a negative ionization mode during the LC-MS and/or LC-MS/MS analysis. It is recognized that in certain embodiments, various steps illustrated and described with respect to FIG. 3 can be omitted without deviating from the scope of the disclosure herein. It is further recognized that in some embodiments, additional steps can be included in the method shown in FIG. 3 that are not illustrated and described.

At step 330, a negative Internal Standard solution (also sometimes referred to herein as “Internal Standard solution”) and a diluent (also sometimes referred to herein as the “first diluent”) is added to one another in a vessel, such as a 1.2 mL test tube as one representative, non-exclusive example. In this embodiment, the first diluent can include a combination of water and methanol.

In one embodiment, the specific drug analytes can include one or more of the following 16 analytes: Amobarbital, Phenobarbital, Pentobarbital, Butalbital, Butabarbital, Secobarbital, Ethyl Sulfate, Ethyl-β-D-glucuronide, Valproic Acid, Chlorothiazide, Furosemide, Hydrochlorothiazide, Lisinopril, Oxipurinol, Ezetimibe and/or Ibuprofen.

The concentration of the negative Internal Standard solution can be varied. In various embodiments, the negative Internal Standard solution can include a plurality of negative Internal Standards mixed together with a solution that includes methanol and water. In various embodiments, the negative Internal Standards that are included in the negative Internal Standard solution can include one or more that are selected from the group consisting of the following 8 Internal Standards: Amobarbital-D5, Phenobarbital-D5, Pentobarbital-D5, Butalbital-D5, Butabarbital-D5, Secobarbital-D5, Ethyl-D5 Sulfate and/or Ethyl-β-D-glucuronide D5.

In one embodiment, the negative Internal Standard solution can have a concentration of approximately 1000 ng/mL. Alternatively, the negative Internal Standard solution can have a concentration that is greater or less than 1000 ng/mL. For example, in non-exclusive alternative embodiments, the negative Internal Standard solution can have a concentration that is between 100 ng/mL and 10,000 ng/mL. In one embodiment, the water that is used in the negative Internal Standard solution can be HPLC-grade water. Additionally, or in the alternative, the methanol that is used in the negative Internal Standard solution can be HPLC-grade methanol. The ratio of the volume of water to the volume of methanol in the negative Internal Standard solution can vary. In one embodiment, the ratio of the volume of water to the volume of methanol in the negative Internal Standard solution can be approximately 1:1. However, in alternative embodiments, the ratio of the volume of water to the volume of methanol in the negative Internal Standard solution can be greater than approximately 5:1, 4:1, 3:1, 2:1 or 1:1. In other alternative embodiments, the ratio of the volume of water to the volume of methanol in the negative Internal Standard solution can be less than approximately 1:5, 1:4, 1:3, 1:2 or 1:1. Still alternatively, the plurality of negative Internal Standards can be mixed with a solution or a compound other than a mixture of water and methanol.

The number of negative Internal Standards included in the negative Internal Standard solution can vary depending upon the number and type of analytes being tested in the dried blood sample. For example, in certain tests that include at least 10 analytes being tested simultaneously, a ratio of the number of analytes being tested to the number of negative Internal Standards in the negative Internal Standard solution can be approximately 2:1. In non-exclusive alternative embodiments, the ratio of the number of analytes being tested to the number of negative Internal Standards in the negative Internal Standard solution can be approximately 2:1, or the ratio can be greater than approximately 2:1 or less than approximately 2:1.

Further, the relative volumes of the negative Internal Standard solution and the diluent can be varied. In one embodiment, the volume of the negative Internal Standard solution can be approximately 10% of the volume of the first diluent that is used. For example, in one non-exclusive embodiment, 20 μL of the negative Internal Standard solution can be added together with 200 μL of the first diluent to make a total of 220 μL in the vessel. However, it is recognized that the total volume can be varied as necessary, provided the ratio of the volume of the Internal Standard solution to the volume of the first diluent is the same. However, in alternative embodiments, the volume of the Internal Standard solution can be greater or less than 10% of the volume of the first diluent that is used.

In this embodiment, the first diluent can be HPLC-grade water mixed with HPLC-grade methanol. In one embodiment, the water-methanol mixture can be approximately 20% water and 80% methanol by volume. In non-exclusive alternative embodiments, the ratio of the volume of water to volume of methanol in the diluent can be less than approximately 20:80, or less than approximately 10:90. In still other alternative embodiments, the ratio of the volume of water to volume of methanol in the first diluent can be greater than approximately 20:80, greater than approximately 30:70, greater than approximately 40:60 or greater than approximately 50:50.

At step 332, the dried blood sample is added to the combination of the negative Internal Standard solution and the first diluent. The form of the dried blood sample can vary. In one non-exclusive embodiment, the dried blood sample can include a Mitra® clamshell blood-absorbing tip manufactured by Neoteryx® that has absorbed a relatively small volume of blood from a patient. For instance, in certain embodiments, the blood-absorbing tip can hold approximately 10-50 μL of blood. It is recognized, however, that any suitable means of obtaining and/or storing a blood sample from a patient can be used. The amount of blood that is used to generate the dried blood sample can vary. In one embodiment, the dried blood sample can be generated from an initial amount of blood that is approximately 20 μL. Alternatively, the dried blood sample can be generated from an initial amount of blood that is approximately 10 μL, 30 μL or 50 μL. Still alternatively, the dried blood sample can be generated from an initial amount of blood that is less than 10 μL or greater than 50 μL. In the embodiment that utilizes a Mitra® clamshell blood-absorbing tip, the blood-infused tip is immersed in the vessel with the combination of the negative Internal Standard solution and the first diluent.

At step 334, the vessel that contains the dried blood sample and the combination of the negative Internal Standard solution and the first diluent is sonicated. One or more vessels, each containing a dried blood sample and a combination of the negative Internal Standard solution and the first diluent, can be sonicated simultaneously. Deionized water can be set to approximately 4 degrees Celsius (or higher or lower, as needed), and would be at a sufficient level so that the deionized water is higher than the tip containing the dried blood sample. In one embodiment, sonication can proceed for a total of 2-5 minutes, and can cycle on for 20 seconds and off for 10 seconds. Alternatively, the sonication process can have a duration of less than 2 minutes or greater than 5 minutes. Still alternatively, the on cycle can have a duration of greater or less than 20 seconds, and/or the off cycle can have a duration of greater or less than 10 seconds. During the sonication process, the amplitude setting can be between 70-100%. In one embodiment, the amplitude setting can be approximately 75%.

At step 336, the dried blood sample is removed from the vessel and can be discarded, yielding a final sample.

At step 338, a portion or all of the final sample from step 336 from a particular vessel can then be analyzed by LC-MS and/or LC-MS/MS in a negative ionization mode to detect the presence, absence and/or quantity of a plurality of different analytes in the dried blood sample. In various embodiments, the negative ionization mode of the LC-MS and/or LC-MS/MS process can simultaneously determine the presence or absence of at least 2 analytes in the dried blood sample. In various non-exclusive alternative embodiments, utilizing the method(s) outlined herein, the negative ionization mode of the LC-MS and/or LC-MS/MS process can simultaneously determine the presence or absence of at least 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 or greater than 16 analytes in the dried blood sample. Using the methodology provided herein, a ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of blood from which the dried blood sample was obtained can be at least approximately 2:5. In non-exclusive alternative embodiments, the ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of blood from which the dried blood sample was obtained can be at least approximately 4:5, 2:1, 3:1 or 5:1.

In certain embodiments, the LC-MS and/or LC-MS/MS process can yield evidence of the presence or absence of any single analyte, any combination of analytes, or all of the analytes listed and/or described herein during a single LC-MS and/or LC-MS/MS analysis. The analytes present in the final sample can be determined by any suitable method, including, but not limited to, consulting a lookup table, printouts from the LC-MS and/or LC-MS/MS process, appropriate software, etc.

The volume of the final sample that is needed for LC-MS and/or LC-MS/MS can vary. In various embodiments, the volume of the final sample that is needed is dependent upon the number of analytes being detected and/or analyzed during the LC-MS and/or LC-MS/MS process. For example, in one embodiment, a ratio of the number of analytes to the volume of a portion of the final sample (in μL) that is used during a single LC-MS and/or LC-MS/MS analysis is at least approximately 1:2. In non-exclusive, alternative embodiments, the ratio of the number of analytes to the volume of the portion of the final sample (in μL) that is used during a single LC-MS and/or LC-MS/MS analysis can be less than approximately 1:2. Still alternatively, the ratio of the number of analytes to the volume of the portion of the final sample (in μL) that is used during a single LC-MS and/or LC-MS/MS analysis can be less than approximately 1:3, 1:4 or 1:5, or greater than approximately 1:1, 2:1 or 3:1. Thus, a relatively large number of analytes can be analyzed during the LC-MS and/or LC-MS/MS process using a relatively small volume of the final sample from step 336. In this manner, numerous retests or reruns of step 338 can occur, if necessary.

FIG. 4 is a flow chart showing another embodiment of a method for qualitative and quantitative multiplexing of drug analytes from a urine sample using a negative ionization mode during the LC-MS and/or LC-MS/MS analysis. It is recognized that in certain embodiments, various steps illustrated and described with respect to FIG. 4 can be omitted without deviating from the scope of the disclosure herein. It is further recognized that in some embodiments, additional steps can be included in the method shown in FIG. 4 that are not illustrated and described. In one embodiment, the specific drug analytes can include one or more of the following 16 analytes: Amobarbital, Phenobarbital, Pentobarbital, Butalbital, Butabarbital, Secobarbital, Ethyl Sulfate, Ethyl-β-D-glucuronide, Valproic Acid, Chlorothiazide, Furosemide, Hydrochlorothiazide, Lisinopril, Oxipurinol, Ezetimibe and/or Ibuprofen.

In certain non-exclusive embodiments, the method for qualitative and quantitative multiplexing of drug analytes from a urine sample can include one or more of the following steps.

At step 440, a negative Internal Standard solution (also sometimes referred to herein as “Internal Standard solution”) and a urine sample are added to one another in a vessel, such as a 1.2 mL test tube as one representative, non-exclusive example. The preparation of the negative Internal Standard solution can be substantially similar or identical to preparation of the Internal Standard solution previously described relative to step 330 in FIG. 3.

The number of negative Internal Standards included in the negative Internal Standard solution can vary depending upon the number and type of analytes being tested in the urine sample. For example, in certain tests that include at least 10 analytes being tested simultaneously, a ratio of the number of analytes being tested to the number of negative Internal Standards in the negative Internal Standard solution can be approximately 2:1. In non-exclusive alternative embodiments, the ratio of the number of analytes being tested to the number of negative Internal Standards in the negative Internal Standard solution can be approximately 2:1, or the ratio can be greater than approximately 2:1 or less than approximately 2:1.

The ratio of the volume of the Internal Standard solution and the urine sample can vary. In one embodiment, the ratio of the volume of the Internal Standard solution and the urine sample can be approximately 1:1. However, in non-exclusive alternative embodiments, the ratio of the volume of the Internal Standard solution and the urine sample can be greater than approximately 1:1, 2:1, 3:1, 4:1 or 5:1. Still alternatively, the ratio of the volume of the Internal Standard solution and the urine sample can be less than approximately 1:1, 1:2, 1:3, 1:4 or 1:5.

At step 442, a diluent is added to the mixture of the negative Internal Standard solution and the urine sample from step 440 to form a final sample. In various embodiments, the diluent can be a solution that includes water and methanol. In one embodiment, the water that is used can be HPLC-grade water. Additionally, or in the alternative, the methanol that is used can be HPLC-grade methanol. The ratio of the volume of water to the volume of methanol in the diluent can vary. In one embodiment, the ratio of the volume of water to the volume of methanol in the diluent can be approximately 1:1. However, in alternative embodiments, the ratio of the volume of water to the volume of methanol in the diluent can be greater than approximately 5:1, 4:1, 3:1, 2:1 or 1:1. In other alternative embodiments, the ratio of the volume of water to the volume of methanol in the diluent can be less than approximately 1:5, 1:4, 1:3, 1:2 or 1:1. Still alternatively, the diluent can comprise compounds other than a mixture of water and methanol.

Further, the relative volumes of the mixture of the negative Internal Standard solution and the urine sample on the one hand, and the diluent on the other hand, can be varied. In one embodiment, the volume of the mixture of the negative Internal Standard solution and the urine sample can be approximately 25% of the volume of diluent that is added. For example, in one non-exclusive embodiment, 20 μL of the negative Internal Standard solution can be added together with 20 μL of the urine sample and 160 μL of the diluent to make a total of approximately 200 μL in each vessel. However, it is recognized that the total volume can be varied as necessary. However, in alternative embodiments, the volume of the mixture of the negative Internal Standard solution and the urine sample can be greater or less than approximately 25% of the volume of diluent that is added.

At step 444, a portion or all of the final sample from step 442 from a particular vessel can then be analyzed by LC-MS and/or LC-MS/MS in a negative ionization mode to detect the presence and quantity of a plurality of analytes in the urine sample. In various embodiments, the negative ionization mode of the LC-MS and/or LC-MS/MS process can concurrently yield evidence of at least 2 analytes in the urine sample. In various non-exclusive alternative embodiments, utilizing the method(s) outlined herein, the negative ionization mode of the LC-MS and/or LC-MS/MS process can concurrently yield evidence of at least 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 or greater than 16 analytes in the urine sample. In certain embodiments, the LC-MS and/or LC-MS/MS process can yield evidence of the presence or absence of any single analyte, any combination of analytes, or all of the analytes listed and/or described herein during a single LC-MS and/or LC-MS/MS analysis. The analytes present in the final sample can be determined by any suitable method, including, but not limited to, consulting a lookup table, printouts from the LC-MS and/or LC-MS/MS process, appropriate software, etc.

The volume of the final sample that is needed for LC-MS and/or LC-MS/MS can vary. In various embodiments, the volume of the final sample that is needed is dependent upon the number of analytes being detected and/or analyzed during the LC-MS and/or LC-MS/MS process. For example, in one embodiment, a ratio of the number of analytes to the volume of a portion of the final sample (in μL) that is used during a single LC-MS and/or LC-MS/MS analysis is at least approximately 1:1. In non-exclusive, alternative embodiments, the ratio of the number of analytes to the volume of the portion of the final sample (in μL) that is used during a single LC-MS and/or LC-MS/MS analysis can be less than approximately 1:1. Still alternatively, the ratio of the number of analytes to the volume of the portion of the final sample (in μL) that is used during a single LC-MS and/or LC-MS/MS analysis can be less than approximately 1:2, 1:3 or 1:4, or greater than approximately 2:1, 3:1 or 4:1. Thus, a relatively large number of analytes can be analyzed during the LC-MS and/or LC-MS/MS process using a relatively small volume of the final sample from step 442. In this manner, numerous retests or reruns of step 444 can occur, if necessary.

It is understood that although a number of different embodiments of the method for qualitative and quantitative multiplexing of drug analytes from biological samples have been illustrated and described herein, one or more features of any one embodiment can be combined with one or more features of one or more of the other embodiments, provided that such combination satisfies the intent of the present invention.

While a number of exemplary aspects and embodiments of the method for qualitative and quantitative multiplexing of drug analytes from biological samples have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope. 

What is claimed is:
 1. A method for qualitative and quantitative multiplexing of drug analytes from a dried blood sample, the method comprising the steps of: mixing an Internal Standard solution with a first diluent in a vessel, the Internal Standard solution including a plurality of different Internal Standards; adding the dried blood sample to the vessel; sonicating the vessel containing the Internal Standard solution, the first diluent and the dried blood sample; removing the dried blood sample from the vessel so that a final sample can be attained; and analyzing at least a portion of the final sample using one of LC-MS and LC-MS/MS to simultaneously determine the presence or absence of a plurality of different analytes in the dried blood sample.
 2. The method of claim 1 wherein the Internal Standard solution includes a plurality of Internal Standards.
 3. The method of claim 1 wherein the Internal Standard solution includes at least 15 Internal Standards.
 4. The method of claim 1 wherein the Internal Standard solution includes at least 25 Internal Standards.
 5. The method of claim 1 wherein the Internal Standard solution includes at least 50 Internal Standards.
 6. The method of claim 1 wherein the dried blood sample is generated using less than 50 μL of blood.
 7. The method of claim 1 wherein the dried blood sample is generated using less than 20 μL of blood.
 8. The method of claim 1 wherein the dried blood sample is generated using less than 10 μL of blood.
 9. The method of claim 1 wherein the first diluent is methanol.
 10. The method of claim 1 wherein the first diluent includes water and methanol.
 11. The method of claim 10 wherein a ratio of the volume of the water to the volume of the methanol is less than 1:1.
 12. The method of claim 10 wherein a ratio of the volume of the water to the volume of the methanol is approximately 1:4.
 13. The method of claim 1 further comprising the step of adding a second diluent after the step of removing the dried blood sample from the vessel.
 14. The method of claim 13 wherein the second diluent is water.
 15. The method of claim 14 wherein the volume of the second diluent is substantially similar to the volume of the first diluent.
 16. The method of claim 1 wherein the step of analyzing includes simultaneously determining the presence or absence of at least 15 different analytes.
 17. The method of claim 1 wherein the step of analyzing includes simultaneously determining the presence or absence of at least 60 different analytes.
 18. The method of claim 1 wherein the step of analyzing includes simultaneously determining the presence or absence of at least 90 different analytes.
 19. The method of claim 1 wherein the step of analyzing includes simultaneously determining the presence or absence of at least 130 different analytes.
 20. The method of claim 1 wherein the step of analyzing includes using one of LC-MS and LC-MS/MS in a positive ionization mode.
 21. The method of claim 1 wherein the step of analyzing includes using one of LC-MS and LC-MS/MS in a negative ionization mode.
 22. The method of claim 1 wherein a ratio of the number of analytes for which the presence or absence is being determined to the number of Internal Standards in the Internal Standard solution is at least approximately 2:1.
 23. The method of claim 1 wherein a ratio of the number of analytes for which the presence or absence is being determined to the number of Internal Standards in the Internal Standard solution is at least approximately 5:1.
 24. The method of claim 1 wherein a ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of the final sample being analyzed is at least approximately 2:1.
 25. The method of claim 1 wherein a ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of the final sample being analyzed is at least approximately 5:1.
 26. The method of claim 1 wherein a ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of blood from which the dried blood sample was obtained is at least approximately 4:5.
 27. A method for qualitative and quantitative multiplexing of drug analytes from a dried blood sample, the dried blood sample being obtained from not greater than 20 μL of blood, the method comprising the steps of: mixing an Internal Standard solution with a first diluent in a vessel, the Internal Standard solution including a plurality of Internal Standards; adding the dried blood sample to the vessel; sonicating the vessel containing the Internal Standard solution, the first diluent and the dried blood sample; removing the dried blood sample from the vessel so that a final sample can be attained; and analyzing at least a portion of the final sample using one of LC-MS and LC-MS/MS to simultaneously determine the presence or absence of a plurality of different analytes in the dried blood sample; wherein a ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of blood from which the dried blood sample was obtained is greater than approximately 3:1.
 28. The method of claim 27 wherein the ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of blood from which the dried blood sample was obtained is at least approximately 9:2.
 29. The method of claim 27 wherein the ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of blood from which the dried blood sample was obtained is at least approximately 6:1.
 30. A method for qualitative and quantitative multiplexing of drug analytes from a dried blood sample, the dried blood sample being obtained from less than 20 μL of blood, the method comprising the steps of: mixing an Internal Standard solution with a first diluent in a vessel, the Internal Standard solution including a plurality of Internal Standards; adding the dried blood sample to the vessel; sonicating the vessel containing the Internal Standard solution, the first diluent and the dried blood sample; removing the dried blood sample from the vessel so that a final sample can be attained; and analyzing at least a portion of the final sample using one of LC-MS and LC-MS/MS to simultaneously determine the presence or absence of at least 16 different analytes in the dried blood sample; wherein a ratio of the number of analytes for which the presence or absence is being determined to the volume (in μL) of blood from which the dried blood sample was obtained is greater than approximately 3:1. 